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Influenza viruses are common pathogens causing respiratory infections in humans. Among the four seasonal influenza viruses, influenza A virus H3N2 has become the leading cause of seasonal influenza illness and death, posing a great threat to public health and the economy. Since it first emerged and caused a pandemic in 1968, H3N2 has been circulating repeatedly in human beings and continually evades host immune attack by antigenic drift, resulting in a decrease in vaccine efficacy. In this paper, the antigenic evolution of influenza A virus H3N2, the impact of antigenic evolution on the selection of vaccine strains and some models for predicting the evolution of influenza viruses were analyzed and reviewed, which paved the road for understanding the antigenic evolution of influenza virus and vaccine development.
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Objective@#To discuss the characteristics of symptoms improvement based on the follow-up evaluation of Eustachian tube balloon dilation medium to long-term efficacy in patients with symptomatic Eustachian tube dysfunction (SETD).@*Methods@#Patients from 2015 to 2017 were followed up after Eustachian tube balloon dilation (with the sense of aural fullness, or tinnitus and hearing ambiguity). All participants had been done ETDQ-7 before surgery and were re-evaluated with ETDQ-7 in follow-up. The improvement of overall and individual symptoms scores in ETDQ-7, the effects of gender and the difference of scores at different stages (12-18 months, 18-24 months and 24-30 months) after the operation were analyzed.@*Results@#There were 29 patients, including 16 males and 13 females, whose age ranged from 20 to 62 years old. The medium to long-term score of ETDQ-7 significantly declined after surgery (27.0±7.9 vs. 14.1±7.5, P<0.05). Among all symptoms, symptoms like "blockage feeling in ear or being like under the water, constriction feeling" , "sound of blisters or explosions in the ear" decreased obviously (P<0.05). Comparing different stages after surgery, the scores of ETDQ-7 existed no difference (P>0.05). And the difference of gender showed no significant influence on surgery effects.@*Conclusion@#The subjective symptoms of patients with Eustachian tube dysfunction diagnosed with SETD can be significantly improved in the medium to long-term follow-up after Eustachian tube balloon dilation, and the degree of improvement is not linearly related to the postoperative time.
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Objective:To analyze the neutralization properties of different genotypes and mutants of severe fever with thrombocytopenia syndrome virus (SFTSV).Methods:Pseudoviruses of SFTSV of different genotypes and mutants were constructed using VSVΔG-Fluc*G backbone. Neutralization assays were established based on the pseudoviruses. DNA vaccines for different SFTSV genotypes were prepared. Serum samples were collected from guinea pigs immunized with the DNA vaccines. Neutralizing antibodies in serum samples from immunized guinea pigs and naturally infected patients were detected using neutralization assays and analyzed.Results:The pseudoviruses of five genotypes and 43 mutants were successfully constructed and the neutralization assays based the pseudoviruses were successfully established after optimizing the reaction parameters. The dilution multiple corresponding to the inhibition rate of neutralizing antibody to half of the pseudovirus infection was taken as the titer of neutralizing antibody by the reduction in pseudovirus reporter gene. The neutralization antibody titers in naturally infected patients and immunized guinea pigs were respectively in the ranges of 1∶100-1∶43 000 and 1∶100-1∶2 500 when detected with the reference HB29 pseudovirus. The neutralization antibody titers ranged from 1∶100-1∶2 500 after immunization with different genotypes of DNA vaccines. No significant statistical difference in neutralization antibody titer was observed among different genotypes or mutant strains.Conclusions:The neutralization properties of different genotypes and mutants showed no significant change, which would be very useful for developing vaccines.
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Antibody dependent enhancement (ADE) is a common phenomenon in virology. It is involved in the mechanisms of infections caused by Dengue virus (DV), severe acute respiratory syndrome coronavirus (SARS-CoV), influenza virus, HIV and other viruses and affects the research and development of vaccines against them. Because the pre-existing specific antibodies or antibodies at sub-neutralizing titer can enhance the infectivity of viruses, leading to disease aggravation, vaccination may promote infection instead of preventing it. This article focused on the impact of ADE on the research and development of vaccines and the assessment of ADE.
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The ongoing pandemic of Coronavirus disease 19 (COVID-19) is caused by a newly discovered β Coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). How long the adaptive immunity triggered by SARS-CoV-2 can last is of critical clinical relevance in assessing the probability of second infection and efficacy of vaccination. Here we examined, using ELISA, the IgG antibodies in serum specimens collected from 17 COVID-19 patients at 6-7 months after diagnosis and the results were compared to those from cases investigated 2 weeks to 2 months post-infection. All samples were positive for IgGs against the S- and N-proteins of SARS-CoV-2. Notably, 14 samples available at 6-7 months post-infection all showed significant neutralizing activities in a pseudovirus assay, with no difference in blocking the cell-entry of the 614D and 614G variants of SARS-CoV-2. Furthermore, in 10 blood samples from cases at 6-7 months post-infection used for memory T-cell tests, we found that interferon γ-producing CD4
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Adult , Aged , Female , Humans , Male , Middle Aged , Adaptive Immunity/physiology , Antibodies, Neutralizing/blood , COVID-19/immunology , Cohort Studies , Immunoglobulin G/blood , SARS-CoV-2/immunology , T-Lymphocytes/physiology , Time Factors , Viral Proteins/immunologyABSTRACT
Human papillomavirus (HPV) infection is the most common sex-transmitted virus infection. Persistent infection of HPV could cause cancers in different parts of the body, such as cervix and anus. Up to now, three prophylactic HPV vaccines have been approved to prevent HPV infection and related diseases. It is well accepted that neutralizing antibodies are the mediator of protection. Analysis of immunogenicity has been playing a key role in HPV vaccine clinical trials, especially in the evaluation of durability of immune responses, immunobridging in young girls and boys, and reduced-dose schedules. There is still no unique method for the evaluation of immunogenicity of HPV vaccines in clinical trials. The data of immunogenicity from different clinical trials cannot be compared directly. It is urgently needed to establish a high throughput and protection-related unique assay as well as standard materials for its standardization. To accelerate the development and evaluation of prophylactic HPV vaccines, a standardized method should be well validated and transferred to different laboratories to make clinical immunogenicity data comparable.
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Cervical cancer is the second most common cancer in women worldwide. It is clear that persistent infection of high-risk human papillomaviruses (HR-HPVs) is the main cause for this disease. Among the several HPV types associated with carcinoma, HPV-16 is the most prevalent type and present in about 50% of tumor specimens. The major capsid protein (L1) of HPV can self-assemble into virus-like particles (VLPs) with immunogenicity similar to infectious virions. Neutralizing epitopes are the structural basis of the current prophylactic HPV vaccines. The efficacy of HPV vaccines is critically dependent upon the integrity of type-specific neutralizing epitopes. Recently, considerable headway has been made in studying the epitopes of HPV16 based on neutralizing antibodies. Notably, more and more HPV16 variants have appeared along with increasing immune pressure. To study the phenotypic variations in HPV16 L1 protein, 1 204 naturally occurring sequences were analyzed and a phylogenetic tree was then constructed including four clades. Moreover, after compared the aforementioned sequences with the 114K reference sequence, eight "hot mutation sites" , six "specialized mutation sites" and 20 "epitope-related mutation sites" were found. Generally, sera raised against VLPs can neutralize the corresponding HPV types, but not other types. However, it is not known whether intragenotypic variants of human papillomavirus type 16 (HPV-16) can be neutralized by sera vaccinated with a single variant VLPs. It is, therefore, imperative to understand the neutralizing epitopes and intragenotypic variants of HPV-16 for the production of prophylactic vaccines with high potency and broad coverage.
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Objective@#To validate a pseudovirus-based neutralization assay for the detection of antibodies against human papillomavirus (HPV) in human serum samples.@*Methods@#The specificity, accuracy, precision, range of linearity, limit of detection and robustness of the neutralization assay were evaluated using HPV-negative serum samples, vaccinated serum samples with quadri-valent vaccine, and international standards for detecting antibodies against HPV16 and HPV18.@*Results@#Based on the data of the HPV-naïve samples, the criteria of positivity was determined as follows: the 50% inhibitory dose (ID50) of the tested sample was not less than 40 and 2-fold not less than that for bovine papillomavirus. The neutralization assay showed good accuracy with a recovery rate of 87%-122% and excellent reproducibility with intra- and inter-assay variation of 5%-27% and 10%-26% respectively. The HPV16 and HPV18 international standards were used to define the limit of quantification, which was 1.28 IU/ml for HPV16 and 0.96 IU/ml for HPV18. Acceptable ranges of variation for the key parameters of this assay were defined, which showed the good robustness of the pseudovirus-based neutralization assay.@*Conclusion@#The pseudovirus-based neutralization assay for the detection of HPV antibodies showed good specificity, accuracy, sensitivity, and robustness, suggesting that it could be used to evaluate the immunogenicity of HPV vaccines.
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Objective@#To investigate the presence of hepatitis E virus (HEV) RNA and HEV antigen (HEV-Ag) and to evaluate the infectivity of HEV in urine through a SPF rabbit model of HEV infection.@*Methods@#Serum, fecal and urine samples collected from SPF rabbits with HEV infection were tested for viral and biochemical markers using real-time RT-PCR and ELISA. Liver and kidney biopsies were performed for observing histopathological changes and immunohistochemical staining. Rabbits were challenged with HEV isolated in urine samples to evaluate the infectivity.@*Results@#Rabbit R1# that was injected with rabbit HEV presented viremia, fecal shedding of HEV, high serum level of HEV-Ag, elevated aspartate transaminase (AST) and alanine transaminase (ALT) and typical symptoms of hepatitis. Urine samples of rabbit R1# continued to be positive for HEV RNA and HEV-Ag. Ratios of HEV-Ag to RNA in urine samples of rabbit R1# were significantly higher than those in serum and feces samples. The parameters quantified in routine urinalysis remained within the normal ranges in rabbit R1#. However, pathological changes and the presence of HEV-Ag were observed in kidney tissues. Furthermore, serum and fecal samples that were collected from one of the two rabbits injected with rabbit R1# urine-derived HEV were HEV positive and the virus strains isolated form feces remained infective to rabbits.@*Conclusion@#HEV infection may result in kidney injury and the urine may pose a risk of transmission. HEV-Ag detection in urine may be valuable for the diagnosis of ongoing HEV infection.
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Marburg virus (MARV) is a lethal virus that causes fatal hemorrhagic fever.It belongs to the Filoviridae family which also includes Ebola virus.MARV is similar to Ebola virus in structure and infection mechanism.Moreover,the diseases caused by them have similar clinical symptoms.However,researches on MARV are less than those on Ebola virus.In this review,we focus on the viral structure,especially the structure of MARV glycoprotein (GP) which determines its infectivity,functions of MARV GP as well as protective antibodies and vaccines against this protein.
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Objective To establish HIV-1 seroconversion panels with the samples collected by National Institutes for Food and Drug Control ( NIFDC) and to evaluate the window periods of HIV enzyme immunoassay ( EIA) diagnostic kits used for blood screening with them. Methods Serum specimens were collected from different plasma donation stations in China. All suspected HIV infection specimens were screened for HIV by using the nucleic acid amplification testing (NAT), Western blot confirmatory assay and P24 quantitative detection assay. The HIV env gene sequences were amplified by RT-PCR for further confirmation of HIV infection. The PCR products were sequenced and genotyped. The confirmed seroconver-sion panels were used to evaluate the early detection capabilities of the 4th and 3rd generation HIV EIA diag-nostic kits used in blood screening in china. Results A total of 8 sets of HIV seroconversion panels com-prised of 36 samples were confirmed in this study, including 6 sets of AE subtype, 1 set of B subtype and 1 set of unknown genotype. Those seroconversion panels were tested with HIV diagnostic kits produced by 19 different manufacturers. For the early detection of HIV infection, the 4th generation HIV diagnostic kits with a score of 9. 4 points were better than the 3rd generation HIV diagnostic kits whose score was 3. 6 points (P<0. 01, t=8. 547). Some of the domestic 4th generation HIV diagnostic kits were similar to the imported kits in the early detection of HIV infection. In terms of the diagnosis of HIV infection, the HIV-1 NAT was at least 2 weeks earlier than the HIV EIA diagnostic kits. The sensitivity of confirmatory assay was lower than that of the diagnostic kits. Four out of five 4th generation HIV diagnostic kits showed declined signal to cut off ( S/CO ) ratio , indicating the probability of false detection during the second window period . Conclusion Eight sets of NIFDC HIV-1 seroconversion panels were established in this study. With those panels we found that there were differences in the window period between different EIA diagnostic kits used for HIV blood screening.
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Objective To analyze the practicability of using ELISA kit for the detection of hepati-tis E virus antigen ( HEV-Ag) in plasma donations and Biomex HEV seroconversion panels. Methods The HEV-Ag positive samples were screened out from 36 340 donated blood plasma samples. Real-time fluores-cent PCR was performed for the detection of HEV RNA in HEV-Ag positive samples. The open reading frame 2 (ORF2) in HEV RNA was amplified by nested RT-PCR and the amplified products were confirmed by sequencing analysis. Phylogenetic tree was constructed for HEV genotyping. Five Biomex HEV serocon-version panels were used in this study for the detection of HEV-Ag, anti-HEV antibody and HEV RNA as well as the correlation analysis between HEV-Ag and HEV RNA. Results Twenty-six out of 36 340 plasma samples (0. 07%) were positive for HEV-Ag. Of the 26 samples, 25 samples were positive for HEV RNA as indicated by the results of nested RT-PCR and 23 positive samples were confirmed by sequencing analysis. The positive rate of HEV RNA in blood plasma donators was 1 ∶ 1 580 (0. 06%). There were 17 samples of genotype 1 (74%) and 6 samples of genotype 4 (26%) according to the phylogenetic tree analysis. All of the HEV-Ag positive samples were also positive for HEV RNA as indicated by the analysis of Biomex sero-conversion panels. HEV-Ag was consistent with the peak of the HEV RNA concentration. Conclusion A close relationship between HEV-Ag and HEV RNA was observed. HEV-Ag screening could be used as a measure to reduce the risk of HEV transmission by blood transfusion.
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Objective To establish a high throughput phenotypic test for the detection of drug re-sistance in human immunodeficiency virus(HIV)strains. Methods The gene encoding luciferase was in-activated through restriction enzyme digestion and ligation. LacZ gene was used to replace the genes encoding original protease and reverse transcriptase. pol genes were amplified from pSG3△env plasmid and cloned in-to a new backbone plasmid through infusion. The factors that might affect the results of the test were opti-mized. Results The parental backbone plasmid pNL4-3. Lac was constructed,of which the gene encoding luciferase was inactivated and bearing the LacZ gene instead of genes encoding protease and reverse tran-scriptase. Several influential factors including cell numbers(10 000 / well),virus inoculation(200 TCID50 /well)and the concentration of DEAE-dextran(15 μg/ ml)were optimized. The reproducibility of this test was confirmed by testing 12 anti-HIV drugs against 2 pseudovirus strains 8 times,presenting the coefficient of variations(CVs)from 4. 32% to 28. 46% . Six types of pseudovirus were constructed and tested against the 12 anti-HIV drugs,the results of which were compared with those by using the pSG3△env-based pseud-ovirus test. The results of the two tests presented good consistency. Conclusion The high throughput phe-notypic test based on pNL4-3. Lac plasmid,combining the advantages of pSG3△env and pNL4-3 systems, could be used to analyze the drug resistance patterns of HIV-1 infectors and screen new drugs for antiretrovi-ral therapy in a rapid and effective way.
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Objective To sequence and analyze the full-length genome of one HEV strain,W2-1 isolated from a sporadic hepatitis E patient hospitalized in 1999 in Xinjiang,China.Methods Nested RT-PCR assays with 4 sets primers were used to amplify the entire genome.The PCR products were purified and sequenced.The full-length genome was acquired by assembling the fragmental sequences using the DNAstar 5.01 software.The genome of W2-1 was analyzed by comparing with the reference HEVs from GenBank.Results The complete genome of W2-1 is 7212 nt in length,including three open reading frames (ORF1-3) with 5079,1980 and 345 nt respectively,27 nt 5'UTR and 83 nt 3'UTR,and a 3' poly A tail.Phylogenetic analysis based on full-length genome showed that W2-1 belonged to genotype 1,subtype 1b.W2-1 had high homology with the HEV strains isolated in the large hepatitis E epidemic in Xinjiang in 1987-1989,sharing 97.2％-98.5％ nucleotide identity in the full length genome.W2-1 also showed high homology with 1b strains isolated in China after 2000,with 97.6％-99.2％ nucleotide identity.The specific amino acid sites in ORF1-3 proteins that distinct between genotype 1 HEV and the potential zoonotic strains did not change in W2-1.Conclusion W2-1 belongs to subtype 1b.The study indicates subtype 1b HEV has been circulating in China in a long period after hepatitis E outbreak in Xinjiang in 1986-1989.The amino acids of ORF1-3 of subtype 1b are conserved.
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Objective To study the in vivo expression and biodistribution of Ad5-Fluc (Adenovirus carrying firefly luciferase genes) in mice.Methods The recombinant Ad5-Fluc virus was constructed and infected to BALB/c or nude mice through three different routes.The protein expression level,tissue distribution and the characteristics of infection were analyzed by in vivo bioluminescence imaging technology.Results Compared to other two routes,the BALB/c mice infected through muscular route had the longest expression cycle (over 60 days) and the highest expression level,while the virus was transferred into the liver and spleen after infection.The nude mice had a significantly extended expression cycle than BALB/c mice.Moreover,the characteristic of liver tropism was eliminated after Ad5 F35 infection in mice,while maintained similar expression efficiency.Conclusion Due to the highest expression efficiency,the muscular route would be the optimal route for Ad5 vector based vaccination.In addition,Ad5F35 virus could become an ideal alternative vaccine vector for eliminating the liver tropism.
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Objective To compare cellular immune responses in mice elicited by Chinese different AIDS candidate vaccines.Methods According to their different immunization procedures,BALB/c mice were immunized with 6 AIDS candidate vaccines,separately.Spleen cells were isolated for the detection of cellular immune response to HIV-specific peptides using enzyme-linked immunosorbent spot(ELISPOT)assay and intracellular cytokine staining(ICS)method.Results AIDS vaccines were evaluated by using potential T-cell epitopes(PTE)Gag,Env and Pol peptides pool and ELISPOT.The positive conversion rates for cellular immune response of 1#-6# vaccines fluctuated from 70% to 100%.The vaccine-induced cellular immune responses to specific peptides pool are different not only in magnitude but also in breadth.The Th1type cytokines,IFN-γand IL-2,were detected with ELISPOT in 1# and 2# vaccines.The productions of IFN-γand IL-2 induced by both of the two vaccines showed a moderate correlation(r1 =0.62,P1 ＜0.01 ;r2=0.79,P2 ＜ 0.01).The positive conversion rate of IFN-γ secreting cells of 1 # vaccine was 66.7%(10/15)mice detected with both ELISPOT and ICS.And the results tested by ELISPOT and ICS showed moderate correlation(r = 0.55,P ＜ 0.05).Conclusion The magnitude and breadth of cellular immune responses induced by different AIDS candidate vaccines are different.Being induced by different AIDS candidate vaccines,the IFN-γand other Th1 type cytokines detected by ELISPOT or ICS could be used to evaluate the cellular immune responses in mice.
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Objective To evaluate anti-HEV IgG and IgM diagnostic kits with sera from convalescent hepatitis E patients and to establish the quantification method of detecting anti-HEV lgG.Methods Detect 42 convalescent serum samples of over 6 months after onset of hepatitis E patients from Jiangsu province with anti-HEV IgM and IgG diagnostic kits. Select and mix the anti-HEV IgG positive sera which were confirmed by Western blot with ORF2 and ORF3 antigen. The mixed serum was calibrated with a WHO anti-HEV Ig standard. A series quantitative linear standard was made for quantitative detection of anti-HEV IgG in hepatitis E vaccine clinical trials phase Ⅲ. Results The positive rates of the anti-HEV IgG di-agnose kits of G, K, MP, Wantai were 71.4%, 78.6%, 92.9% and 100% respectively. The positive rates of G was lower than that of MP (χ~2 = 5.19, P<0.05) and obviously lower than Wantai (χ~2 = 11.76,P<0.01). The positive rates of K was also obviously lower than that of Wantai (χ~2 =7.96, P <0.01).The positive rates of the anti-HEV IgM diagnose kits of MP, G, X, Wantai, K were 21.4%, 7.1%,21.4%, 64.3%, 78.6% respectively. The positive rate of both K and Wantai were obviously higher than that of MP(χ~2 = 15.75 ,P<0.01 ; X2 = 27.43 ,P< 0.01). With the Western blot confirmation test, 30 and 18 sera were reactive to ORF2 and ORF3 antigen separately. The anti-HEV IgG concentration of HEV-D01 mixed by 13 samples was 57.94 U/ml by the calibration. Prepare seven 1.5-fold dilution series of quantita-tive linear standard for HEV vaccine clinical trials phase Ⅲ, concentration range from 0.077 to 0.877 U/ml. The quantitive values of high, medium and low concentrations quality control samples lay in the range of average ± 2s, and the CV of quantitative values were 16%, 16%, 12% respectively. Conclusion The quality of different anti-HEY IgM and IgG diagnose kits were different. This study had set up a set of anti-HEV IgG linear quantitative standard, which fit for detecting anti-HEV IgG antibodies quantitatively in HEVvaccine clinical trial phase Ⅲ.
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Objective To compare the sensitivity, specificity and consistency of five kits for quantitative detection of hepatitis B virus (HBV) DNA. Methods Four domestic fluorescence kits, A, B, C, and D, and Roche Cobas Ampliprep/Cobas TaqMan HBV test for quantitation of HBV DNA in serum, were applied to detect the National Standards, an additional plasma for sensitivity (7 times dilution), 15 plasma samples from healthy blood donor and 45 plasma samples from chronic hepatitis B patients. Results All five kits showed the correct results for the 9 positive specimens and 8 negative specimens from the National Standards. The quantitative results of specimens for sensitivity met requirements of the National Standards. The lowest concentration of HBV DNA by these three kits was 15.6 IU/mL. The lowest detection level of HBV DNA for domestic kit B was ≤500 IU/mL. There was linear correlation between the results by Roche kit and domestic kit C (r> 0.98). Kit D showed 2 false-negatives results in the 15 healthy blood donor samples. The coincidence rates between 4 domestic kits and the Roche kit ranged from 50% to 96% (A: 61%, B: 50%, C: 96%, D: 83 %). The consistency rate of kit C with the Roche kit was significantly higher than those of kit D, A and B (X2=5.62, P<0.05, X2=28. 93, P<0.01, X2=44.31,P<0.01, respectively). The consistency rates among these 5 kits were highest when testing samples with HBV DNA levels between 1×104-1×107 IU/mL. Conclusions The qualities of domestic kits vary remarkably and kit C has the greatest consistency rate with the Roche kit. Therefore, the qualities of domestic kits need to be further improved.